1. Field of the Invention
The invention relates to water supply manifolds for supplying water to a plurality of spaced fittings and, more particularly, relates to a water supply manifold of the type typically used in a cage and rack system for housing lab animals and the like and to a method for the water supply manifold""s production.
2. Discussion of the Related Art
Water supply manifolds are used in a variety of applications. One such application is a cage and rack system in which animals, such as laboratory rats or laboratory mice, are housed in a plurality of rows of cages mounted on vertically spaced shelves. Some systems have two rows of cages positioned back-to-back on each shelf. All of the cages on a particular rack may be supplied with water from a common water supply manifold and ventilated via a common air exhaust manifold and a common air supply duct. The water supply manifold of this type of system is typically serpentine in shape, consisting of several horizontal legs that are mounted on the shelves and that are linked to one another by vertical legs located at the ends of the shelves. Each horizontal section of the manifold includes a header tube and spaced fittings that extend radially from the header tube and into the associated cages. In systems in which each shelf supports two rows of cages, each header tube extends along the center of the shelf between the two rows of cages, and two circumferentially opposed fittings supply water to both cages at each water supply location on each shelf. Each animal watering valve is coupled to the manifold via a fitting arrangement including a saddle fitting that is permanently welded onto a header tube of the manifold.
Fabricating and assembling a water supply manifold usable in a cage and rack system and other, similar applications often entails a rather time consuming process. A saddle fitting must be welded onto the associated header tube at each water supply location, and a hole must then be punched through the fitting and through the wall of the header tube to produce a flow path for water through the fitting from the header tube. The welding process used to attach the saddle valve to the header tube is a rather time consuming process requiring significant skilled labor and/or complex equipment. In the case of a manifold having fittings on both sides thereof, it is also nearly impossible to perfectly align the fittings on the opposite sides of the manifold with one another. Accordingly, at each water supply location on the manifold, two holes must be punched from opposite sides of the header tube. Thus, a first hole must be punched in the header tube through a first fitting, the header tube must be rotated 180xc2x0, and a second hole must be punched in the header tube through the second fitting. Only then can the header tube be indexed to position the next fitting receiving location in the punching location.
The punching process also tends to distort the header tube to separate the header tube wall from the saddle weld connecting the fitting to the header tube, thereby forming a xe2x80x9cdead spacexe2x80x9d between the weld and the header tube in which water may accumulate and foster bacterial growth. This bacterial growth may endanger the health of animals supplied with drinking water.
The need therefore has arisen to provide a water supply manifold that can be produced easily and quickly while at the same time ensuring adequate seals between the manifold""s header tube and the associated fitting. The need has also arisen to provide a method for rapidly producing tubular water supply manifolds that results in an improved end product.
In accordance with a first aspect of the invention, an improved water supply manifold is provided that lacks traditional welded saddle fittings. The water supply manifold instead includes a cylindrical header tube having a number of spaced apertures, each of which is surrounded by an at least generally planar depressed surface portion or xe2x80x9cflat.xe2x80x9d It further includes a plurality of fittings, each of which has an inlet which is in fluid communication with an associated one of the apertures and an axial upstream end surface which is disposed outside of the header tube and which is sealed against the flat adjacent to the associated aperture. This relationship negates the need for an additional saddle weld and eliminates any dead spaces at the juncture between the header tube and the fitting in which water could otherwise accumulate and foster bacterial growth.
In order to negate the need for any weld and to further facilitate assembly, the fitting preferably is threaded onto or otherwise attached to a supply tube that extends through the associated aperture so as to have an inlet opening disposed within the header tube and an outlet opening that empties into the fitting. If the water supply manifold is of the type in which two opposed fittings are located at each water supply location along the manifold, the supply tube preferably extends completely through the header tube such that opposed outlet ends of the supply tube extend from two circumferentially opposed radially aligned apertures in the header tube. This arrangement negates the need for a separate supply tube for each fitting, thereby considerably reducing the number of parts and accelerating assembly. It also negates the need to attach the support tube to the header tube.
A single supply tube can be employed at each water supply location of a two row system only if the apertures in the opposite sides of the header tube are perfectly or nearly perfectly aligned with one another. In accordance with another aspect of the invention, a method of manufacturing the water supply manifold assures adequate alignment of the apertures at each water supply location by forming a single through-hole entirely through the header tube at each water supply location for the insertion of a water supply tube through the thus-formed apertures in the header tube. In order to obtain the benefit of a dead space-free seal between the fitting and the header tube, the hole forming step also is preferably accompanied by a collapsing step that forms the above-described flat around the apertures in the header tube. Both steps can be performed via a fully automated hole piercing process that automatically pierces the through hole and that forms the opposed flats.
These and other objects, advantages, and features of the invention will become apparent to those skilled in the art from the detailed description and the accompanying drawings. It should be understood, however, that the detailed description and accompanying drawings, while indicating preferred embodiments of the present invention, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications.